不必要的

Quantum mechanics, continuum and cosmological models provide evidence that no general approach is in sight.

量子力学，连续介质力学和宇宙模型证明，没有普遍适用的方法。

The paper summarizes studies of in vitro inducement of haploids in cucurbitaceae, including anther culture, in vitro gynogenesis culture and induction of haploid obtained by irradiated pollen. The factors affectting in vitro inducement such as material genetype, medium, pretreatment, megaspores development stage and others had significant effects on the embryoids inductivities.

重点对葫芦科植物离体诱导单倍体的研究进行综述，包括花药培养、离体雌核培养、辐射花粉诱导单倍体培养等在育种中的应用，以及供体基因型、培养基、预处理方式、胚囊发育时期等因素对离体诱导再生频率的影响。